13,905 research outputs found

    Conformal Anomaly Of Submanifold Observables In AdS/CFT Correspondence

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    We analyze the conformal invariance of submanifold observables associated with kk-branes in the AdS/CFT correspondence. For odd kk, the resulting observables are conformally invariant, and for even kk, they transform with a conformal anomaly that is given by a local expression which we analyze in detail for k=2k=2Comment: 11 p

    Sharjah, U.A.E.: the urban conservative dilemma

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    This thesis has two broad aims, to outline and analyse the urban development of the city of Sharjah, United Arab Emirates, illuminating significant events leading to the establishment and subsequent spatial expansion of the settlement. This analysis provides the basis from which the second part of the thesis is derived, thus fulfilling the second aim; to create a series of conservation zones in the city based upon the historical, architectural and cultural significance of groups of buildings, plus their feasibility for preservation according to their physical condition. It is to attempt to redress the balance of the wholesale demolition of historic areas of Middle-Eastern cities that this thesis is offered, in the hope that the suggestions contained within may provide, at the very least, a stimulus or springboard that could result in the extension and application of ideas to other Gulf cities, so resulting in the regional development of conservation zones. Chapters 1.1, 1.2 and 2 trace the establishment and development of the settlement called Sharjah, outlining significant historic events and their geographical impact upon the town, including the Master Plan of 1959.Chapter 3 widens the approach, comparing the town to others in the Middle East with respect to components considered to be essential elements of urban cores ('medinas').Chapters 4, 5 and 6 analyse these individual components; religious institutional buildings, suqs and residential structures, collating evidence to create proposed conservation zones based on both broad-based patterns and individual case studies to exemplify such findings in detail. Chapter 7 outlines potential problems of large-scale conservation schemes, offering some possible solutions but significantly, presenting the dilemma common to many such cities: the conflict of land use at the heart of the city: its historic urban core. Chapter 8 concludes the thesis by summarizing all previous evidence and submitting up-to-date findings from a field visit in 1991, thus illustrating any significant developments with respect to conservation in the city

    Unique continuation results for Ricci curvature and applications

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    Unique continuation results are proved for metrics with prescribed Ricci curvature in the setting of bounded metrics on compact manifolds with boundary, and in the setting of complete, conformally compact metrics. Related to this issue, an isometry extension property is proved: continuous groups of isometries at conformal infinity extend into the bulk of any complete conformally compact Einstein metric. Relations of this property with the invariance of the Gauss-Codazzi constraint equations under deformations are also discussed.Comment: 32 pages, supercedes math.DG/0501067; final published versio

    Variational Principles for Natural Divergence-free Tensors in Metric Field Theories

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    Let Tab=Tba=0T^{ab}=T^{ba}=0 be a system of differential equations for the components of a metric tensor on RmR^m. Suppose that TabT^{ab} transforms tensorially under the action of the diffeomorphism group on metrics and that the covariant divergence of TabT^{ab} vanishes. We then prove that TabT^{ab} is the Euler-Lagrange expression some Lagrangian density provided that TabT^{ab} is of third order. Our result extends the classical works of Cartan, Weyl, Vermeil, Lovelock, and Takens on identifying field equations for the metric tensor with the symmetries and conservation laws of the Einstein equations

    Framing employment research using behavioural science

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    The main aim of this thesis is to explore the structured use of behavioural science in helping to frame employment research. This structured framing intended to help stimulate more interdisciplinary interaction between sub-disciplines that study employment and behavioural science, setting out new empirical and theoretical applications to the study of employment decision-making. Firstly, the application of specific behavioural science concepts to employment scenarios, structured around the core facets of behavioural science, introducing the types of bias studied in behavioural science in turn. These core facets are cognitive and social biases, risk preferences and biases, time preferences and biases. These were combined with illustrative examples of how these biases might affect employment decision-making. The employment cycle is then used to demonstrate how the concepts in behavioural science may play out across a range of employment scenarios, unearthing potential theoretical and empirical applications. A behavioural science framing was then used to investigate factors related to the addition or omission of low rated journal publications in the assessment of academic resumes. The results of these investigations showed that low rated journal publications are still of some value, albeit journal ratings play a crucial role. Importantly, the extent to which additional low rated journal publications are valued could depend on unconscious social biases that are based on prior expectations, potentially dictated by organizational and ideological learning over time. The empirical work presented data collected from 1,011 psychology and management faculty based at U.K. and U.S.A. universities. The data was collected using an online randomized control trial survey experiment designed to test the assessment of publication records on academic resumes. Only faculty at levels likely to be involved in academic appointment panels and reviewing academic resumes were contacted to take part

    Textured Surfaces for Ultrasound Haptic Displays

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    We demonstrate a technique for rendering textured haptic surfaces in mid-air, using an ultrasound haptic display. Our technique renders tessellated 3D `haptic' shapes with different waveform properties, creating surfaces with distinct perceptions

    Organisational culture in English further education: chimera or substance

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    Since the mid-1970s there has been a greater emphasis placed on markets and competition as a means of allocating scarce resources. As a consequence of this the provision of public services has come under close scrutiny. In the English further education sector there has been structural and strategic change. The further education (FE) colleges are positioned to be able to play a key role in· the economic and social regeneration of the UK. The development- of 'managerialism' has occasioned the use of many practices and procedures more commonly associated with the private sector provision of goods and services. This study examines whether the concept of organizational culture has meaning and validity in a further education context. Research in this area is complex, time consuming and expensive. The concept of organizational culture is examined and evidence is gathered from a case study in Templeton College. The analysis of the evidence employs some of Pierre Bourdieu's concepts of the social world: field habitus and game. The evidence suggests that there is no integrated pattern of shared beliefs or behaviours that can claim to be a distinct entity. External factors are more likely to determine the situated social practices that exist within colleges. The case study approach has limited the external validity of the research and further analysis of . colleges is needed to verify the claims in this thesis. The study demonstrates that the migration of private sector management practices and concepts to the public sector is not an unproblematic process. FE would benefit from more extensive practitioner research; the more widely and deeply the colleges understand themselves the better chance for securing lasting improvements. Organizational culture is unlikely to be a significant lever of change in FE and colleges may be better advised to build a teaching and learning ethos

    Unique continuation and extensions of Killing vectors at boundaries for stationary vacuum space-times

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    Generalizing Riemannian theorems of Anderson-Herzlich and Biquard, we show that two (n+1)(n+1)-dimensional stationary vacuum space-times (possibly with cosmological constant ΛR\Lambda \in \R) that coincide up to order one along a timelike hypersurface \mycal T are isometric in a neighbourhood of \mycal T. We further prove that KIDS of M\partial M extend to Killing vectors near M\partial M. In the AdS type setting, we show unique continuation near conformal infinity if the metrics have the same conformal infinity and the same undetermined term. Extension near M\partial M of conformal Killing vectors of conformal infinity which leave the undetermined Fefferman-Graham term invariant is also established

    Volume renormalization for complete Einstein--K\"ahler metrics

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    For a strictly pseudoconvex domain in a complex manifold we define a renormalized volume with respect to the approximately Einstein complete K\"ahler metric of Fefferman. We compute the conformal anomaly in complex dimension two and apply the result to derive a renormalized Chern--Gauss--Bonnet formula. Relations between renormalized volume and the CR QQ-curvature are also investigated.Comment: Minor corrections to the statements and proofs of the main theorem and corollary. Included the example of the Bergman metric on the ball. To appear in Differential Geometry and Its Application
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